How to Tune Engine of Pulsar

bubusam13

Human
Hi Guys, someone using Bajaj Pulsar, can you guide me how to tune the engine of Bajaj Pulsar bikes. Pls don't ask to visit service center. They ruined my bike. I am ready to take the risk of tuning myself. Just guide me how to do.
 

Samarth 619

Modrator @ Xbhp Biking
So, you want to tune the bike's carburettor? But, tell me the problem first. Is it running rich or lean?

If your bike is running rich (more petrol:less air), it will go slower, heavier & lethargic but engine will remain cool. Spark plugs will show too much blackness.

If your bike is running lean (lesser petrol:more air), it will go faster initially when cold, but will heat up more and lose power too. Too much riding in this condition can lead to lesser engine life, engine oil loss, etc. Spark plugs show very light or no brown tint.


Identify the symptoms and tell me if your bike needs tuning or not. Then, I'll show you with an image, how to tune a bike's carb. I also have a Pulsar 180 UG3 (now modified to 208cc by a block piston change) and an aftermarket exhaust.
While installing the block-piston kit, I also had to tune the carb, including changing the main jet to a bigger one.
 
OP
bubusam13

bubusam13

Human
i think its running rich since spark plugs show black residue.
Again yesterday my bike engine stopped while running. I tried self and kick, both didn't worked. Self even doesnot work at morning of after parking it few hours. When I try self, the digital display too switch off as if self is using lots of power. Mechanic said my battery is ok. Could there be problem with the self itself like formation of carbon etc ?
 

Samarth 619

Modrator @ Xbhp Biking
See, self start doesn't appear to be a problem, as carbon is formed in the combustion area (above), not where the self start motor rotates the crankshaft (below). Although, self starting motor may be corrupted by other ways like rusting, etc. But as of now, let's check engine problems & AFR, as you said it didn't start using kick also.

Let me give you a small maintenance tip: Always start and warm up your bike for 30 seconds at idle rpm (no accelerator) before riding it off.
This way, oil circulates the engine well before you rev it higher and the engine life is enhanced.

As for your problem, let's go step by step:

1. Start your bike, Warm it up like I said above, and then rev it till 6000-7000 rpm in neutral on stand. Which color's smoke do you see from the exhaust?

If you're seeing white or Blue+Grey smoke constantly, stop the bike immediately and take it to the nearest service station and tell them to check & accordingly replace its Valve Seals/ Guides/ Piston Rings/ cylinder's internal walls and the PCV System.
They should understand everything, except for PCV. PCV system is a crankcase ventilation system, and it is actually a pipe coming out of crankcase connected to the air filter box, so that moving piston doesn't cause vaccum in the crankcase, or allow small amount of leaked gases to escape the chamber.
If it is blocked or twisted, oil may get sucked up in the combustion chamber or combustion gases might not escape.
Ensure that its not blocked or twisted. Its a black pipe.


BUT luckily, If you see black smoke (rich) or no smoke at all (normal or lean), then its thankfully fine. Proceed towards the next step.


2. Check the screw as shown in the image below:

*imageshack.us/a/img607/5089/030820123302.jpg

Forget the "unlock the screws" text in the above image, but do you notice the "AFR screw"?

Try tightening it BUT REMEMBER THE NUMBER OF TURNS it is on, right now. A normal "non-modified" Pulsar should have about 3-4 full turns loosened, from the fully tight position.
After measuring its number of turns to fully tightened position, RESTORE it back to the original number of turns, ok? Its very important.

Tell me,
1. How many turns was your AFR screw tightened originally (all these days)?
2. And what color smoke did you see while revving your bike after warm up? Did the smoke disappear after some seconds or it continued on..?
3. Also, can you post your spark plug's pic?

Then, I'll tell you what to do further step by step. (I hope you're not getting impatient. Carb tuning is a complicated process & I can't hurry it up).
 

dashing.sujay

Moving
Staff member
^what's the idle rpm you keep ? Last time I got my bike serviced, the mechanic tuned it upto ~2k rpm. Mileage drastically went down from 35 to 20. (I own RTR 160). Then I got it decreased to ~1.1 or so. Is it ok? and what are the other two screws (except AFR) for ?
 
OP
bubusam13

bubusam13

Human
^^Its less than 2k and grater than 1 k that you should keep. 1.5k

@ Samarth 619
Thanku thanku thanku very much. You know the picture you posted is the only picture over the internet about how to tune Pulsar. I was searching for it for 2 years.
Hey I solved my problem today. I found that my battery is dry completely. So put acid and water. Also air filter was very dirty, so cleaned it. My bike is back to form.

And I dont see any coloured smoke. Spark plug had dark residue, so more oil, less air right ? lets see few days since I cleaned air filter today.
And how should I turn the AFR, clockwise or anticlockwise ? And since it was before not starting at kick, should battery really can be the problem ? ANd another question is whenever I start my bike after a long rest, like in morning, my RPM touches 4k-5k without even acceleration. It stays like that for a few minutes and then comes to idle RPM. Is it normal ?

and give me sometime, I will tighten the AFR, I have holiday on 13th
 
Last edited:

Samarth 619

Modrator @ Xbhp Biking
^what's the idle rpm you keep ? Last time I got my bike serviced, the mechanic tuned it upto ~2k rpm. Mileage drastically went down from 35 to 20. (I own RTR 160). Then I got it decreased to ~1.1 or so. Is it ok? and what are the other two screws (except AFR) for ?
My Idle rpm is around 1k rpm for a cold started engine, and 1.5k for a heated up engine (by heated up I mean, when its daytime and you have run it for 5-10 kms). Its ideal according to manuals.

The other two screws on the lower part? They are for opening the carburetor's lower column, and replacing the "MAIN JET". Fuel supply should be off when you open this cover.

Actually, if you have to make major changes to the AFR (specially when you install a modification component, like K&N air filter, performance exhaust, etc.) then you have to change the main jet to a bigger holed one. I have changed the main jet on my Pulsar 208 to get its AFR right.
AFR screw can only make minor to medium difference to your Air Fuel Ratio, not major. Hence, Main jet had to be changed to a bigger one.

^^Its less than 2k and grater than 1 k that you should keep. 1.5k

@ Samarth 619
Thanku thanku thanku very much. You know the picture you posted is the only picture over the internet about how to tune Pulsar. I was searching for it for 2 years.
Hey I solved my problem today. I found that my battery is dry completely. So put acid and water. Also air filter was very dirty, so cleaned it. My bike is back to form.

And I dont see any coloured smoke. Spark plug had dark residue, so more oil, less air right ? lets see few days since I cleaned air filter today.
And how should I turn the AFR, clockwise or anticlockwise ? And since it was before not starting at kick, should battery really can be the problem ? ANd another question is whenever I start my bike after a long rest, like in morning, my RPM touches 4k-5k without even acceleration. It stays like that for a few minutes and then comes to idle RPM. Is it normal ?

and give me sometime, I will tighten the AFR, I have holiday on 13th
Acid and Water? Well, I suggest that when your battery expires, get a maintenance free battery. I got an Amaron with a 5 year warranty, for Rs. 1600 few years back and so far, it has never given me a problem. Even a wired battery recharge was not needed, as the battery never became weak. It works like a charm.

As for the pic, I snapped it myself on my own pulsar and uploaded it on my imageshack a/c. I had to make this pic for helping someone at Xbhp, a biking site where I'm a junior moderator.
And, when your rpm raises itself only on the morning starts, it could most probably mean that your bike has autochoke, and it is working normally. :)

Just for your knowledge, twisting the AFR screw:

* Clockwise- will tighten it and make it run lean (lesser fuel : more air),
* Anti clockwise- will open the screw, make it richer (more fuel : less air).

Carb tuning is a complicated process, don't hurry it. My Pulsar 208 gives me a mileage of around 40 kmpl with hard riding & good throttle response and one button starts in the morning. That was achieved, when I tuned it according to a certain procedure for 5-6 days after I modified it.

I suggest that you don't twist the AFR screw yourself right now, or make very minimal adjustments only, like upto half a circle turn clockwise (since you said spark plug shows black residue). Just observe your bike for some days, and try checking its performance & engine temperature...
 

koolent

Youngling
For the best setting I guess is when the spark plug is neither Back nor Light brown, It should be Dark brown. Close to black, but not black and then you will have the perfect mix.

Bought my Apache RTR 160 Hyper Edge yesterday. Tuned the Clutch, Accelerator play, Idle Screw and the AFR Screw. Remember the initial position and even a 3/4th turn will give you better starts (like my Apache does give) however I have done only a 1/2 turn, it shows a great improvement.

Since your bike is old, get it fully checked and replace any required part. Take a look at the engine oil specs and get a better engine oil with the same (ex: Viscosity, Synthetic, Semi-Synthetic etc.) Usually Castrol, Valvoline etc. would be better. Clean the oil filter if you haven't already and if you think misfires occur, time to get a new plug!

Go ahead on DIY Section on the MyPulsar website and learn how stuff works. I Learnt to adjust the Clutch from there only :p

Read up, long way to go! START :)
 

nitin007

Right off the assembly line
hey...samarth19...how r u...i need ur help....i m having a pulsar 150 dts-i es 2005model...:lol: actually the problem in bike is it's carburetor....whenevr i start bike and try to run in 1st and 2nd gear my bike give hiccups:-(...i've tuned afr and spark plug colour is dark chocolate brown but giving more carbon in sparking area....i've cleaned filter also...but problem is remain....there was some water in fuel tank...so i cleaned tank and carb also...but of no use...so pls help me...one more thing i wanna add that my bike never give me perfect idling like 1000rpm cold/1500rpm hot...i always have to ue accelerator or it goes up like 2000rpm can directly mail me to nitinrajpoot007@gmail.com or message me on facebook.com/nitnrajpoot007
 

neel911

New to this forum
Hi Samarth,

I own a pulsar 180 UG3. Last time I gave my bike for service the person while delivering my bike told that there was no engine oil in my bike. Are there any chances that my bike is consuming engine oil. If yes then how will I get to know.
Please help me with this.

Waiting for your reply.

Regards,
Neel
 

Samarth 619

Modrator @ Xbhp Biking
hey...samarth19...how r u...i need ur help....i m having a pulsar 150 dts-i es 2005model...:lol: actually the problem in bike is it's carburetor....whenevr i start bike and try to run in 1st and 2nd gear my bike give hiccups:-(...i've tuned afr and spark plug colour is dark chocolate brown but giving more carbon in sparking area....i've cleaned filter also...but problem is remain....there was some water in fuel tank...so i cleaned tank and carb also...but of no use...so pls help me...one more thing i wanna add that my bike never give me perfect idling like 1000rpm cold/1500rpm hot...i always have to ue accelerator or it goes up like 2000rpm can directly mail me to nitinrajpoot007@gmail.com or message me on facebook.com/nitnrajpoot007
I'm sorry I can't mail.

Switch the fuel knob to off. Get the carburetor drained using the Drain screw in the bottom of the carb. Use it only when bike is cold. Some fuel will drain out. And some mixed water too hopefully.
This should solve the problem.

Hi Samarth,
I own a pulsar 180 UG3. Last time I gave my bike for service the person while delivering my bike told that there was no engine oil in my bike. Are there any chances that my bike is consuming engine oil. If yes then how will I get to know.
Please help me with this.

Waiting for your reply.
Regards,
Neel
Engines without engine oil don't survive a lot. The best I've seen is 20 minutes of riding, after which the engine seized.

The best measure right now, would be to to full up engine oil and see where is it leaking...

1. If its leaking from the engine (through the piston rings into combustion area) portion, you will see GREY or BLUE smoke from the exhaust on high acceleration. Then, you will need to get the piston rings changed. Maybe it might also involve changing of Piston and cylinder block. Only your mechanic can advise more on this matter.

(A little white smoke on immediate starts after rains, is no cause for worry as its the water evaporating.)

2. If its leaking from the crankcase, then you will spot it leaking. Have a look under the bike for it.
 

athul.m

Right off the assembly line
I have a 2006 model pulsar 180 ,my bike is losing engine oil n engine heat up fastly even with sufficient oil . I think my bike is running lean .throttle response is low n it has hiccups in initial gears .idle rpm is 1000 or below .pls help me to tune my bike correctly
 

Samarth 619

Modrator @ Xbhp Biking
I have a 2006 model pulsar 180 ,my bike is losing engine oil n engine heat up fastly even with sufficient oil . I think my bike is running lean .throttle response is low n it has hiccups in initial gears .idle rpm is 1000 or below .pls help me to tune my bike correctly
Firstly, check the exhaust of your bike, because Pulsars usually develop problems with the exhaust. If there are cracks or if glasswool (they look like hairs) leaks from the exhaust hole or if there's a different sound, it might suggest a physical damage to exhaust.

Idle rpm can be increased by a simple hand operated twistable knob on the carburetor. Make it to around 1000-1100 for a cold bike, but best way would be to ride 3-5 kms to make the engine hot, and then set it to 1400-1500.
If its mistuned or modified, it might be running lean. A mechanic can solve this if he knows what AFR (Air Fuel Ratio) means and how to work on it.
Other symptoms could be due to clogging in the air filter. Get it cleaned and examined.

Engine oil is not lost due to a slightly lean-running bike... Engine oil lost could be due to 2 reasons and the solutions are also mentioned:-

1. Engine oil might be leaking from below the bike. If so, spot the location and seal it or get it repaired.

2. Engine oil might be sneaking into the combustion chamber. If this happens, you will also see a different colored smoke from the exhaust. This would mean that the piston rings could be collapsed or breaking with time. Replace them. Depending on your bike's age and usage, it might require a piston or a block change too.

I must have posted my guide about tuning the carburetor & AFR correctly... Its not a very complicated process, but it requires patience and testing.. I think it must be somewhere here only.
 

Abhinays

Right off the assembly line
Hi samarth 619,
I have pulsar 180 UG4 (2011), I am facing a different problem, I have read and tried your tip for setting my carb's FRP screw but strangely when I turn the screw full closed even then also my bike didnt stall means it didnt turned off and even my ideal screw also not working well can you give me any advise for my problem.
 

Samarth 619

Modrator @ Xbhp Biking
Hi samarth 619,
I have pulsar 180 UG4 (2011), I am facing a different problem, I have read and tried your tip for setting my carb's FRP screw but strangely when I turn the screw full closed even then also my bike didnt stall means it didnt turned off and even my ideal screw also not working well can you give me any advise for my problem.
Hi Abhinay,
What is a FRP screw? Anyhow...

Your idle screw is the one connected to your throttle... Give accelerator, which part on the carb do you see moving, a black ring connected to a wire, right? Idle screw is below that only. Its a big screw, usually hand operate-able.. So, are you operating the correct screw?

As for the AFR, the bike is not always supposed to go off, but if you tighten it fully, the rpm will become unstable, ie. it will go up and down unreliably. The engine will heat up mighty quick too. See if you find these signs.


If you're still confused about AFR, better to ask a good mechanic to tune the AFR... There are various ways to tune the AFR depending on your resources... One such way is pollution meter.

For example, since AFR has an impact on the output of certain gases, you can twist the AFR screw to find where the perfect AFR is, which is 14.7:1.

If you have a CO2 detector (usually Bajaj people have it), insert its pipe in the exhaust, and you must keep the screw at a position where CO2 is maximum. Why?
Because CO2 is maximum when the AFR ratio is near perfect.... Rich or lean means that the CO2 level drops.

See the diagram below, its a very useful diagram, that suggests the volume of each exhaust gas at various stages of AFR, and also the power output at rich and lean settings.
The blackened area is the near perfect zone for the AFR. That's where your vehicle should be...

airfuelratio5big.GIF
 
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